Carburetor



June 6, 1961 R. F. ROY 2,987,304

CARBURETOR .Filed Sept. 2l, 1959 United States liatent O 2,987,304 CARBURETOR Robert F. Roy, 363 Jones Hill Road, West Haven, Conn. Filed Sept. 21, 1959, Ser. No. 841,264 8 Claims. (Cl. 261-44) This invention relates to carburetors for producing and supplying combustible mixtures of air and fuel to internal combustion engines or other devices using combustible mixtures.

It is an object of the invention to provide an improved carburetor that is of simple and compact construction, and easy and inexpensive to manufacture.

It is another object of the invention to provide an improved carburetor that may be utilized in any physical position.

It is still another object of the invention to provide an improved carburetor that may be utilized with either liquid, gaseous or powdered solid fuels, requiring .substitution of only a few parts to do so.

It is still another object of the invention to provide an improved carburetor wherein conventional carburetor components such as chokes, gasoline oats, accelerator pumps, butterfly flutter valves, gaskets and seals are eliminated.

It is still another object of the invention to provide an improved carburetor wherein jet icing and stalling are substantially eliminated.

The above and other objects and further details of that .which I believe to be novel and my invention will be clear from the following description and claims taken with the accompanying drawings, wherein:

FIG. 1 is a side elevational view of a carburetor which incorporates the instant invention;

FIG. 2 is a sectional view taken centrally longitudinally thereof;

FIG. 3 is a perspective view on an enlarged scale of an important component of the carburetor;

FIG. 4 is a top plan view of a portion of the control means for the carburetor which is disposed within the carburetor housing;

FIG. 5 is a sectional view taken substantially on line 5*-5 of FIG. 2, and

FIG. 6 is a fragmentary enlarged view of a portion of FIG. 5 showing the relevant components of a carburetor in idling position.

The improved carburetor is designated generally in the drawings by reference numeral 10, and is illustrated as being oriented in one position. To facilitate explanation, it` will be described with reference to the illustrated position. It should be fully understood, however, that the improved carburetor maybe disposed in any position and may function as either an updraft or downdraft carburetor. Also, the description will proceed on the assumption that the carburetor is utilizing liquid fuel, such as gasoline. However, it should be fully realized that by making some simple substitutions of parts, which will be explained subsequently, it may be utilized with either gaseous fuels, such as propane gas, or powdered sol-id fuels.

i The improved carburetor 10 is extremely simple in construction and may be made in a compact unit. It

-comprises a housing 12 having an elongated passageway 14, which extends generally horizontally in the illustrations. The external configuration of housing 12 may take any desired form. The housing 12, in operational use, may be operatively associated with an internal comand therefore, the end 18of the passageway 14 comprises' ice j an air inlet for the carburetor. The housing 12, at its other end, includes a flanged collar 20 which surrounds the other end 22 of the passageway 14, which comprises an outlet for the air-fuel mixture produced by the carburetor which may communicate with the cylinders of the engine, as by communicating with the intake manifold thereof. Intermediate the ends of the passageway 14 there is formed a Venturi-type constriction 24 which, as

can best be seen in FIGS. 2 and 5, is generally rectangular in cross-sectional configuration.

Fuel admission means is formed adjacent to constriction 24 to permit fuel to enter the passageway 14 and be mixed in the carburetor prior to exiting out outlet 22 to the engine. Adjacent to the constriction 24, an opening 26 is formed in the bottom wall 28, as illustrated, which is generally rectangular in cross-sectional configuration. The opening 26 is closed by a fuel inlet assembly 30, which comprises a anged body 32 having a plurality of communicating bores formed therein, which is secured to the housing 12 by bolts 34 which pass through openings 36 vformed in the flanges 38 of the body 32 and are threadedly anchored in threaded openings 37 formed in housing bottom Wall 28. The `fuel inlet assembly 30 is, therefore, readily removably secured to the carburetor housing 12.

With reference to FIG. 5, it will be seen that the fuel inlet body 32 includes a generally horizontally extending bore 40, the end 42 of which -is disposed to communicate with a fuel supply source of any known suitable form through a conduit (not shown) that may be connected to the fuel inlet body 32 in any convenient known manner. The other end 44 of the bore 40 communicates with co-axially bores 46 and 48, also formed in body 32, the axis of which is disposed normal to the axis of the bore 40. On the upper side of the anges 38, the body 32 has a raised face 50 which is of a rectangular outline to snugly fit within the rectangular opening 26 in the housing bottom wall 28. As can best be seen in FIG. 5, face 50 has a at central raised surface 52 and oppositely inclined flat surface portions 54. When fully mounted on the housing 12, the fuel inlet body 32 closes the opening 26, -but the bores 40, 46 and 48 place the portion of the passageway 14 adjacent the constriction 24, on the downstream side thereof, into communication with the fuel source.

Within the bore 48 there is disposed a fuel inlet jet sub-assembly which facilitates controlled fuel admission. This subassembly preferably comprises a plug 56 and a jet insert 60. Plug 56 is threaded or press-fitted linto the bore 48, and has a bore 58 into which a jet insert 60 is either threaded or press-fitted. The plug 56 has an enlarged head 62 in the form of a truncated cone which includes an upwardly facing, at, annular shoulder 64. The jet insert 60 is generally cylindrical in configuration, includes an axial bore 66, and has a head 68 which projects above the shoulder 64 on the plug 56 and includes a diametre-l groove 70. If the carburetor 10 is to be used with liquid fuel, as this portion of the specification assumes, the jet insert 60 is preferably made of a tempered, hardened metal. However, it is removably mounted in the plug 56, and therefore, other inserts may be substituted for it which are more suitable for use with gaseous or powdered sol-id fuels, as will be subsequently discussed. In any event, it should be noted that the bore 66 in the jet insert 60 at one of its ends communicates with the passageway 14 in the vicinity of the construction 24, and at its other end communicates with the bores 46 and 40 and ultimately with the fuel supply conduit. Therefore, the bore 66 comprises a fuel passageway, and its end that is disposed in the passageway 14 comprises a fuel jet orifice.

The housing 12 includes a vertically extending, transitself in FIG. 3.

3 verse, flat wall 72, as illustrated, which cooperates with a pair of spaced, parallel, flat, side wall portions 74 and a pair of associated shoulders 76, only one of which is shown in FIG. 2, to deline a guideway for a vertically slidably mounted, valve member 78.

The valve member 78 may be most clearly seen by It comprises a flat base wall 80, a pair of spaced, parallel, side walls 82, and a generally V- shaped, front wall 84, all of which may be integrally formed. Front wall 84 includes a central V-shaped channel 86. Disposed centrally between the side walls and formed on the base wall 80 is a pair of spaced upstanding lugs 88. One of the lugs 88 is contiguous with front wall 84 and is designated the front lug, for convenience. The lugs 88 have a pair of coaxial plain bore90 formed therein, and the front wall 84 has an opening 92 that is coaxial therewith. v

A needle 94 is adjustably mounted on the valve member 78 and disposed to extend through bores 90v and,V opening 92. Needle 94 comprises a tapered valve portion 96 and a threaded cylindrical mounting portion 9.8. A threaded adjusting nut 100 is threadedly mounted on the mounting portion 98, and the nut and a coiled compression spring 102, which surrounds part of mounting porvtion 98, are disposed between the lugs 88 after the needle 94 is mounted on the valve member 78 so as to extend through the bores 90 and the opening 92. The fully mounted position of the needle 94 and its associated parts on the valve member 78 can best be seen in FIGS. 2, 3 and 5, and when so mounted, the needle is axially movable in the bores 90 and opening 92, and maintained in a particular position of adjustment by the spring 102 which biases the nut 100 into contact with the front lug 88.

With this mounting of the needle 94, when the car- -buretor is fully assembled, the valve portion 96 projects beyond the front wall 84 into the jet orice and passageway 66, and its position may be manually adjusted by rotating the mounting portion 98 relative to the nut 100. To allow such adjustment, an end of the mounting portion 98 has a kerf 104 formed therein which is disposed adjacent to an opening 106 formed in the top of the carburetor housing 12. Opening 106 normally is closed by a removable closure 108, which is illustrated as comprising a per-forate screen 110 having a pair of mounting washers 112 and a plurality of sets of associated securing screws 114 and lock washers 116. `If desired, a solid re- Y movable plate may be substituted for the particular removslidably movable; such movement is under the selective control of the operator of the device which includes the internal combustion engine, and is effected by control means which may be either hand or foot operated and includes a linkage disposed within the carburetor housing 12 for translating selectively imposed controlling motion of 'the operator into vertical sliding of the valve member 78.

Vertical sliding of valve member 78 results in movement vlof the needle valve portion 96 in the passageway 66. The

presence of the needle valve portion 96 in the passageway 66 results in restriction thereof and of the jet orifice formed thereby. The precise restrictive elect depends `upon the particular amount of needle valve portion 96 that is disposed within the passageway 66, because the largest diameter of the portion 96 that is disposed within,k the passageway 66 determines the amount of restriction.

The linkage disposed Within carburetor housing 12 for sliding the valve member 78 includes a pair of spaced bushings 118 which are mounted on side walls 82 of valve member 78 and pivotally support ends of a pair of spaced links 120, as by means of the pivot pins 12,2. The linkage also includes a U-shaped linkmember 12H4 havingafpair `restricted to the maximum extent. erence to FIG. 6, it will be observed that lthe jet oriice vcommunicates with the passageway 14 only through the of legs 126 having apertured collars 128 that are pivotally disposed on'the pivot shaft 130' which is carried by the other ends of the links 120. The link member 124 includes a cylindrical portion 132 to which is rigidly fixed, as by the fastening pin 134, the transverse rod 136, which in turn extends through openings (unnumbered) in the side walls of the housing 12. At one of its free ends, which is disposed on the exterior of housing 12, the rod 136 is connected to a control lever 138. The control lever 138 forms a part of control means which may take any known convenient foot or hand operated form.

In use of the carburetor, the control lever 138 is pivoted in response to the foot or hand actuation of the operator. Pivoting of the control lever 138 is translated through the linkage means just described into vertical controlled sliding movement of the valve member 78. Three representative positions of the valveV member 78 are illustrated in FIGS. 2 and 5,. The solid line position, which corresponds to the solid line position of the control lever 138 in FIG. l, comprises the fully opened con- `dition of the carburetor; in this condition the effective operating area of both the constriction 24 and the jet orice areV at a maximum (as used herein the term effective operating area means the area of the opening which is unrestricted) and the maximum amount of air and fuel passes through the carburetor. This obtains because the constriction 24 is completely open, and the jet orifice is restricted a minimum amount by valve portion 96 of the needle 94. As was pointed out above, the bore 66 is subject to receiving the valve portion 96 of the needle 94 and being restricted thereby to varying extents depending upon the particular dispositional relationship. In the solid line position illustrated in FIGS. 2 and 5, the jet orifice is open to the maximum for the illustrated needle setting and size of the needle 94 and passageway 66, for only the minimum diameter tip thereof extends into the jet orilce. l

Pivoting of the control lever 138 counter-clockwise, as viewed in FIG. l, to its dotted line position, results in sliding of Vthe valve member 78 downwardly, as viewed Yin FIGS. 2 and 5, to the schematically illustrated dotted line position; such movement is effected through the linkage` means including the link member 124 and links In the dotted line position, the constriction 24 is partially closed by a front portion of the valve mem- `ber 78, and the needle valve portion 96 extends more deeply into the bore 66 of the insert 6 0, and therefore,

va portion thereof of greater diameter is disposed within the jet orifice than in the case of the solid linecondition.

Therefore, the effective operating areas of the constriction 24 and the jet orifice are simultaneously reduced,

' and this results in restricting the How of both air and fuel through the carburetor.

Further movement of the control lever 138 counterclockwise in FIG. l to the dot-dash line position results, through the previously described linkage means, in fur- -ther downward sliding movement of the valve member 78 to its dot-dash position illustrated in FIGS. 2 and 5. In this position the effective operating areas of both the constriction 24 and jet orifice are simultaneously reduced and less air and fuel are allowed to ow through the carburetor. This condition represents a minimum ow condition short of idling."

FIG. 6 illustrates the idling condition of the carburetor, wherein constriction 24 and the jet orifice are With particular refdiametral groove 70 formed in the head 68of jet insert 60, and therefore that a very small amount of fuel is allowed to pass through theY jet orifice into the passage- Y way 14. Also, it will be observed in FIG. 6 that a very small amount of air is allowed to pass through the channel 86 in the front wall 84 of valve member 78 and the groove 70, although some. air; is allowed to pass through the remainder of the restricted constriction 24 around the plug head 62.

In the idling position illustrated in FIG. 6 it should be particularly observed that an annular shoulder 140, which is formed on the needle 94 where valve portion 96 meets mounting portion 98 thereof, is in planar contact with the insert head 68, -and that the needle 94 has been retracted slightly. By comparing FIGS. 5 and 6, it will be observed that the adjusting nut A100 has been forced away from the front lug 88, and that the spring 102 has been compressed when the carburetor is in idling position. Therefore, on subsequent initial movement of the valve member 78 away from the face 50 of the fuel insert body 32 after idling, for a short period the effective operating area of constriction 24 will be increased to allow more air to pass through the passageway 14 before the eifective operating area of the jet orifice is increased, and this eliminates undesirable gas surge on acceleration after idling. This obtains, because on such initial movement of the valve member 78, the relative positions of the needle valve portion 96 and the insert 60 remain unchanged until the valve member 78 has been moved sufliciently away from the face 50 to disengage the needle shoulder 140 from the insert head 68, at which time the spring 102 will have biased the nut 100 into re-engagement with the front lug 88. Thereafter, changes in the effective operation area of both the constriction 24 and jet orifice occur simultaneously.

Three representative physical conditions of the carburetor have been set forth. There are an infinite number of other positions between idling and open throttle which the valve member 78 and needle 94 may take, and in such positions, varying amounts of restriction of the eiective operating areas of the constriction 24 and the jet orifice result, over most of the range of movement of the valve member 78.

When the carburetor is operatively associated with an internal combustion engine, the following structural relationship exists: The collar 16 is connected to a conventional air supply conduit, the fuel inlet assembly 30 is connected to the fuel supply conduit of a conventional liquid fuel supply system, which may -be either of the gravityfeed or forced feed type, and the collar 20 is connected to the engine in any convenient manner, as by placing the passageway end 22 of the carburetor into communication with the usual intake manifold of the engine. Prior to starting the engine, the carburetor will be set in idling condition (see FIG. 6). On starting the engine, the usual hand or foot operated control means is actuated 'by the operator, the valve member 78 is moved upwardly, and a ow of air through the passageway 14 in the carburetor housing 12 (from right to left as viewed in FIG. 2) is induced. Air flowing past the insert head 68 vaporizes the liquid fuel which sprays from the jet orifice into the passageway 14 adjacent the constriction 24 on the upstream side thereof. Liquid fuel is thoroughly vapor-ized and the air-fuel mixture is carried off through the passageway end 22 to the intake manifold. Further actuation of the control means in the accelerating direction results in further movement of the valve member 78 upwardly and simultaneous increases in the effective operating area of both the constriction 24 and the jet orice. This permits a greater ow of air to pass through the constriction 24, and a greater flow of liquid fuel is simultaneously allowed to pass through the jet orifice.

The particular ratio of liquid fuel to air depends principally upon the size and shape of the needle valve portion 96 and the vdiameter of insert bore 66, because the size and shape of the constriction 24 and valve member 78 are fixed. The precise air-fuel ow relationship for the various positions of the valve member 78 may be empirically determined so as to provide the proper taper on the needle valve portion 96 and proper bore 66 diameter. The fuel-air ratio, after once being fundamentally determined for a carburetor of given size, may be further altered by manually adjusting the needle 94; such adjustment is not intended to be made very often, being in the nature of a line adjustment.

Once the basic shape and size of the needle valve portion 96 and insert bore 66, in addition to the constriction 24 and valve member 78, are set, the carburetor will function in a superior manner to known carburetors. This is due in part to the fact that the liquid fuel feed is not dependent on the operation of vacuum-operated, `butterfly flutter valves, and therefore, all of the operational problems incident thereto are eliminated. Superior carburetor operation is also due in part to better vaporization of the liquid fuel than heretofore effected. Better vaporization results from the air stream owing about the yneedle valve portion 96, which is disposed adjacent to the jet orifice and functions to create a considerable amount of turbulence on the downstream side thereof which facilitates vaporization of liquid fuel. Further vaporization of the spray of liquid fuel, which starts to vaporize at the point of Contact with the air stream owing through the passageway 14, occurs as the partially vapon'zed spray is carried downstream and contacts additional lateral portions of the air stream. In addition to providing improved vaporization, the improved carburetor minimizes stalling and substantially eliminates jet icing, which most contemporary carburetors are subject to. Jet icing is substantially eliminated as a result of the self-cleaning eiect of the needle valve portion 96 in the insert bore 66 which results from its reciprocating therein during normal use. It should be noted in this regard that in some relative positions of these parts, the needle valve portion 96 extends completely through the insert bore 66. Furthermore, regardless of the speed at which the engine is running, changes in the ow of air and liquid fuel are uniform, and the air-fuel ratio remains constant.

The improved carburetor possesses additional advantages over known carburetors. In can be made in a small, compact unit which is extremely easy and inexpensive to manufacture. A number of the parts, such as the housing 12, the fuel inlet body 32 and the valve member 78 may be easily and inexpensively die-cast of metal or molded of plastic. Also, the improved carburetor may be utilized in any physical position and may be formed so as to have a multiple number of barrels The improved carburetor does not include any gaskets or seals, and therefore, eliminates the problems inherent in such elements. Also, the improved carburetor does not require chokes, gas floats or accelerator pumps. The range of changes in the ratio of the effective operating areas of the air passage constriction and the liquid fuel jet orice are infinite, and therefore, extremely fine adjustment is permitted.

A particular advantage of the improved carburetor is that it may be utilized with gaseous and powdered solid fuels as well as liquid fuels, with a minimum amount of substitution of parts. In order to adapt the disclosed carburetor, which thus far has been disclosed as utilizing liquid fuel, for use with gaseous fuels, such as propane gas, a plastic insert corresponding to jet insert 60 but having a smaller diameter `bore is substituted for the jet insert 60, and a needle having a valve portion 96 of different taper is utilized. In general, the effective operating area of the jet orice must be smaller for gaseous fuels than for liquid fuels. Nylon is particularly well suited for use as the jet insert material. It is important that the head of the jet insert, regardless of the particular plastic utilized, be resilient so as to permit distortion to temporarily atten and eliminate the groove 70 when the carburetor is inoperative, to thereby prevent the leakage of gaseous fuel when the carburetor is in the inoperative condition.

If powdered solid fuels are utilized, the plug S6 may be .may 'be utilized therewith.

utilized without any jet insert, its bore 58 being used as the fuel passage and jet orifice, and a needle having a valve portion of appropriate taper to cooperate therewith In view of the nature of powdered solid fuels, it is necessary, in general, to provide for a larger effective operating area for the jet orifice when using powdered solid fuels than when using either liquid or gaseous fuels.

The construction of the carburetor is such that any substitutions necessitated by the type of fuel to be utilized may be effected readily, the detachable fuel inlet assembly 30 and closure 108 facilitating such substitution.

As will be evident from the foregoing description, certain aspects of my invention are not limited to the particular details of construction of the example illustrated, and I contemplate that various and other modifications and applications will occur to those skilled in the art. It is, therefore, my intention that the appended claims shall cover such modifications and applications as do not depart from the true spirit and scope of my invention.

Having thus set forth the nature of my invention, I

' claim:

l. A carburetor comprising: a housing; a passageway formed in said housing; an air inlet at one end of said passageway and an air-fuel mixture outlet at the other end thereof; a constriction in said passageway intermediate of said inlet and said outlet; a fuel inlet having a jet orifice adjacent said constriction; and means disposed Within said housing for simultaneously varying the effective operating area of said jet orifice and the effective operating area of said constriction to' vary the volume of air-fuel mixture produced by the carburetor comprising a slidable valve member that is arranged to close and open said constriction, said valve member having a pair of spaced lugs which have a pair of aligned plain bores, a needle adjustably carried by said valve member and having an end arranged to have a po'rtion thereof disposed in said jet orifice, said needle having a threaded portion which extends through said bores, an adjusting nut mounted on said threaded portion, and a spring disposed so as to bias said needle toward said jet orifice and bias said nut into contact with one of said lugs.

2. A carburetor as defined in claim l wherein said `ing formed in said housing.

3. A carburetor as defined in claim 1 wherein said jet Vorifice is formed in a removable insert which forms a part of said fuel inlet.

4. A carburetor as defined in claim l wherein `said needle has an annular shoulder formed thereon which is arranged to contact the portion of said fuel inlet which surrounds said jet orifice just prior to the slidable valve member reaching its position wherein it closes said constrictio'n most fully, whereby on further movement of said slidable valve member to close said constriction most fully said needle is retracted relative to said slidable valve member against the bias of said spring.

5. A carburetor as defined in claim 4 wherein said fuel inlet portion includes a groove which is disposed transversely relative to said orifice.

6. A carburetor as dened in claim 1 wherein said slidable valve member has a V-shaped face having a central channel which is arranged to' maintain a portion of said constriction open and in communication with said jet orifice when said slidable valve member closes said constriction to the maximum extent.

7. A carburetor as defined in claim 1 wherein said means further includes control means 4which is selectively actuated and which includes linkage means within the Vcarburetor housing which is arranged to translate con` trolling motion into sliding motion of said slidable valve member.

8. A carburetor as defined in claim 3 wherein said insert is made of plastic.

References Cited in the le of this patent UNITED STATES PATENTS 2,062,496 v Brokel Dec. l, 1936 2,643,865 Smith et al. June 30, 1953 2,786,658 Duriez Mar. 26, 1957 VFOREIGN PATENTS 137,599 Great Britain Ian. 22, 1920 761,367 Great Britain Nov. 14, 1956 

